The invention relates to an encapsulated granulate which comprises a detergent or cleaning agent active ingredient, in particular an enzyme and/or a bleach activator, to a process for its preparation and to the use of the granulate in solid detergents and cleaning agents.
Besides the good washing and cleaning performance, the consumer expects modern detergents and cleaning agents to also have a positive esthetic impression which manifests itself, in particular, in a scent associated with freshness and cleanliness. In order to comply with this, the compositions normally comprise suitable fragrances. However, a not inconsiderable proportion of consumers disapprove, arguing, inter alia, that fragrances do not contribute to the washing or cleaning result, meaning that their use merely leads to an increase in the price of the compositions. These consumers prefer completely odorless detergents and cleaning agents. However, some ingredients of such compositions have a greater or lesser intrinsic odor which may also be based on minor components present in these ingredients. The use of such ingredients makes an unpleasant impression for fragrance-free compositions and, in the case of fragrance-containing compositions, may lead to an increase in the fragrance concentration in order to compensate for the intrinsic odor.
In connection with this problem, German patent application DE 17 92 074 discloses compositions which comprise zinc ricinoleate as deodorizing active ingredient, the deodorizing action of which is synergistically aided by the addition of other salts or esters of other saturated or unsaturated even-numbered or odd-numbered hydroxylated fatty acids having 17 or more carbon atoms, for example salts and esters of trioxystearic acids.
German patent application DE 25 48 344 discloses the deodorizing effectiveness of metal salts of an unsaturated fatty acid, in particular of metal ricinoleates. Metals from group II of the Periodic Table of the Elements and of the rare earths, such as cerium, lanthanum or neodymium, are preferred. Particular emphasis is given to zinc ricinoleate.
German patent application DE 38 08 114 relates to deodorizing active ingredient mixtures which comprise zinc ricinoleate and optionally the zinc salt of abietic acid and/or further zinc salts of other saturated or unsaturated hydroxylated fatty acids having 17 or more carbon atoms, partial esters of di- or polyhydroxyalkanes, mono- and disaccharides, polyethylene glycols or alkanolamines with the ene adducts of maleic anhydride to at least monounsaturated carboxylic acids having a chain length of from 10 to 25 carbon atoms with an acid number from 10 to 140, and optionally amino and/or amido compounds and remain in clearly dissolved form in preparations with water contents of up to 50% by weight.
Active ingredients which are customarily used in detergents and cleaning agents and in which the occurrence of a more or less unpleasant intrinsic odor cannot always be ruled out include, in particular, enzymes and bleach activators.
Enzymes, in particular proteases, are used extensively in detergents, washing auxiliaries and cleaning agents. Usually, the enzymes are used here not in the form of concentrates, but in mixtures with a dilution and carrier material. If such enzyme preparations are mixed into customary detergents, then a considerable decrease in the enzyme activity may arise upon storage, in particular when bleaching-active compounds are present. The application of the enzymes to carrier salts with simultaneous granulation according to German laid-open specification DE 16 17 190 or by pasting with nonionic surfactants according to German laid-open specification DE 16 17 118 or aqueous solutions of cellulose ethers according to German laid-open specification DE 17 87 568 does not lead to a noteworthy improvement in the storage stability since the sensitive enzymes in such mixtures are generally found on the surface of the carrier substance. Although the storage stability of the enzymes can be significantly increased by encapsulating the enzymes with the carrier material or embedding them into this and then converting them to the desired particle form by extrusion, compression and marumerization, as described, for example, in German patent specification DE 16 17 232, German laid-open specification DE 20 32 768, and the German published specifications DE 21 37 042 and DE 21 37 043. However, such enzyme preparations have only inadequate solubility properties. The undissolved particles can become entangled in the ware and soil it, or they are transferred to the waste-water unused. Although embedding agents known from German laid-open specification DE 18 03 099, which consist of a mixture of solid acids or acidic salts and carbonates or bicarbonates and decompose when water is added, improve the solubility capacity, they are for their part very sensitive to moisture and therefore require additional safety measures.
European patent specification EP 0 168 526 discloses enzyme granulates which comprise water-swellable starch, zeolite and water-soluble granulation auxiliaries. This document proposes a preparation process for such formulations which essentially consists in concentrating a fermenter solution freed from insoluble constituents, admixing said additives, granulating the resulting mixture and optionally encapsulating the granulate with film-forming polymers and dyes, The process with the additive mixture proposed therein is advantageously carried out with fermentation solutions which have been concentrated to a relatively high dry-substance content, for example 55% by weight. In addition, the granulates produced in this way have a sufficiently high rate of dissolution or disintegration under washing conditions that the granulates relatively rapidly disintegrate, sometimes even during storage, and the enzymes are deactivated.
International patent application WO 92/11347 discloses enzyme granulates for use in particulate detergents and cleaning agents which comprise 2% by weight to 20% by weight of enzyme, 10% by weight to 50% by weight of swellable starch, 5% by weight to 50% by weight of water-soluble organic polymer as granulation auxiliary, 10% by weight to 35% by weight of corn flour and 3% by weight to 12% by weight of water. As a result of such additives, the enzyme processing is possible without relatively large losses in activity.
International patent application WO 93/07263 discloses an enzyme-containing granulate which consists of a water-soluble or -dispersible core which is covered with a vinyl polymer, on which there is a layer of enzyme and vinyl polymer, where the granulate has an outer coating made of vinyl polymer. The outer coating may also comprise pigments. However, as a result of the multilayer construction, such an enzyme granulate is relatively complex to produce.
International patent application WO 93/07260 specifies various encapsulation materials for dust-free enzyme granulates which are produced by spraying a fermentation broth onto a hydratable carrier material. Fatty acid esters, alkoxylated alcohols, polyvinyl alcohol, polyethylene glycol, sugars and starch, inter alia, are listed as being suitable.
International patent application WO 95/02031 relates to an enzyme granulate comprising enzyme and inorganic and/or organic carrier material and a uniform outer pigment-containing encapsulation layer which is characterized in that the outer encapsulation layer consists of an encapsulation system which comprises 30% by weight to 50% by weight of a finely divided inorganic pigment, 45% by weight to 60% by weight of an alcohol which is solid at room temperature and has a melting point in the range from 45° C. to 65° C., up to 15% by weight, in particular 5% by weight to 15% by weight, of emulsifier for the alcohol, up to 5% by weight, in particular 0.2% by weight to 3% by weight of dispersant for the pigment and up to 3% by weight of water.
Even if the encapsulation systems described above are usually suitable for stably surrounding enzyme granulates such that no odor emerges from them, the aim is nevertheless to find alternatives, the use of which is as simple as possible and/or leads to cost advantages.